How many semitones is an Augmented Sixth?

Ten — C – A# — the same distance as a minor seventh. Count the semitones of any interval with the interval calculator.

Why is it not written as a minor seventh?

Because the two voices resolve outward to an octave. A minor seventh resolves inward. The spelling tells the performer which way the music is going.

What are the augmented sixth chords?

Italian, French and German sixths — three chords sharing the same outer augmented sixth and differing in their inner voices, all resolving outward to the dominant.

How do I play Augmented Sixth?

On guitar the handiest shape is Next string, B 1 · E 6, read as string and fret; the instrument panel draws it from any starting note with the other shapes. On the piano count 10 semitones up from any key, black keys included. Play the notes together for the harmonic form, one after the other for the melodic form.

What is the inversion of Augmented Sixth?

The inversion of Augmented Sixth is the Diminished Third: put the lower note an octave higher and the distance that remains is the inversion. The two always add up to an octave, 10 semitones and 2 semitones, and swap their qualities between major and minor, or keep perfect as perfect.

Augmented Sixth Interval: How It Sounds, with Song Examples

Play it on your instrument

Loading the keyboard…

From

On the piano, from every note

From	Notes	Play it on your instrument
C	C – A#
C#	C# – A##
D	D – B#
Eb	Eb – C#
E	E – C##
F	F – D#
F#	F# – D##
G	G – E#
Ab	Ab – F#
A	A – F##
Bb	Bb – G#
B	B – G##

Tap a key or a fret to hear it.

Number and quality

An interval has two names. The number counts the letter names from the lower note to the upper one, and the quality counts the semitones inside that number. Augmented Sixth spans 6 letter names, which makes it a sixth, and 10 semitones, which makes it augmented.

DLetter
ELetter
FLetter
GLetter
10 semitones

Read on: number and quality · inversion · compound intervals · consonance and dissonance

Every sixth

A sixth can take these qualities, one semitone apart; choose one to see the upper note move and hear the pair.

Where it lives

Augmented Sixth is in every chord whose formula includes 6A from the root, in every scale that includes it from the tonic, and between these pairs of notes in a major key.

Scales that contain it

C Whole ToneC · D · E · F# · G# · A#

Related intervals

The intervals one step from Augmented Sixth: its inversion, the same sound spelled differently, its simple or compound form, and its nearest neighbours in size.

Diminished Third3d · 2 semitones · C – Ebb
Inversion: together they make an octave
Minor Seventh7m · 10 semitones · C – Bb
The same sound, spelled differently
Augmented Thirteenth13A · 22 semitones · C – A#
The compound form, an octave wider
Major Sixth6M · 9 semitones · C – A
One size away
Major Seventh7M · 11 semitones · C – B
One size away

Open it in a tool

Understanding Augmented Sixth

Names and symbols

Augmented Sixth is written A6, 6A: the letter is the quality, the number the size. Chord formulas on this site write the number first, as tonal does.

Seconds, thirds, sixths and sevenths come in major and minor, a semitone apart, and can be widened to augmented or narrowed to diminished. Inverting one swaps the quality: a major third becomes a minor sixth, a minor second a major seventh.

How it sounds

An augmented sixth spans 10 semitones: C – A#. It sounds like a minor seventh, and it is written as a sixth because its two voices are about to resolve outward, each by a semitone, onto an octave.

How composers use it

The augmented sixth chords — Italian, French and German, distinguished by what sits between the outer voices — all place this interval between the flattened sixth degree and the raised fourth. Both resolve outward onto the dominant, which is the whole point of the device.

The German sixth is enharmonically a dominant seventh chord, which is exactly why it makes such an elegant pivot into a distant key.

Learn this properly

Chapter 14: Chromatic Harmony

Common questions

How many semitones is an Augmented Sixth?: Ten — C – A# — the same distance as a minor seventh. Count the semitones of any interval with the interval calculator.
Why is it not written as a minor seventh?: Because the two voices resolve outward to an octave. A minor seventh resolves inward. The spelling tells the performer which way the music is going.
What are the augmented sixth chords?: Italian, French and German sixths — three chords sharing the same outer augmented sixth and differing in their inner voices, all resolving outward to the dominant.
How do I play Augmented Sixth?: On guitar the handiest shape is Next string, B 1 · E 6, read as string and fret; the instrument panel draws it from any starting note with the other shapes. On the piano count 10 semitones up from any key, black keys included. Play the notes together for the harmonic form, one after the other for the melodic form.
What is the inversion of Augmented Sixth?: The inversion of Augmented Sixth is the Diminished Third: put the lower note an octave higher and the distance that remains is the inversion. The two always add up to an octave, 10 semitones and 2 semitones, and swap their qualities between major and minor, or keep perfect as perfect.